Infection patterns of scabies and tinea between inland and resettled indigenous Negrito communities in Peninsular Malaysia.

Skin infections cause significant health burden and affect underserved communities such as the indigenous Negrito communities disproportionately. There is only one study that has addressed skin infections among the Negrito communities, which is the smallest and most isolated indigenous tribe in Peninsular Malaysia, with approximately 6,500 individuals remaining in northern and central Peninsular Malaysia. This study, which aims to update the infection patterns of scabies and tinea among the Negrito communities, recruited 361 participants from eight villages representing all six Negrito subtribes. The results revealed an overall skin infection prevalence of 35.6%, with scabies (11.7%), tinea versicolor (11.3%), and tinea imbricata (7.5%) as major infections, with no co-infection. Notably, infection rates were significantly higher in resettled villages (55.2%) compared to inland villages (24.8%). Scabies and tinea versicolor were more prevalent in resettled villages (21.2% and 23.6%, respectively) than inland villages (6.4% and 4.7%, respectively), while tinea imbricata was more common in inland villages (9.4% vs 3.9%). Furthermore, there exist predisposition of scabies among Kensiu. High prevalence of tinea imbricata was observed among the inland Bateq while prevalence of tinea versicolor was high among the resettled Bateq. Risk analysis revealed specific associations: scabies with Kensiu subtribe (P = 0.002), high income (P = 0.001) and underweight individuals (P = 0.009); tinea versicolor with Bateq subtribe (P = 0.003), resettled villagers (P < 0.001), males (P = 0.040), and overweight/obese individuals (P = 0.015); and tinea imbricata with Bateq (P = 0.011) and smokers (P = 0.004). These findings highlight a complex interplay between environment and lifestyle in skin infection prevalence. Addressing these infections requires targeted interventions, including regular medical care in inland villages and socio-economic support for resettled communities, considering the distinct predispositions in different village types.

Ascaris lumbricoides harbors a distinct gut microbiota profile from its human host: Preliminary insights.

In indigenous populations where soil-transmitted helminths (STH) infections are endemic, STH parasites (i.e., Ascaris lumbricoides, Trichuris trichiura, hookworms) often co-exist and co-evolve with the gut microbiota of their human hosts. The association between STH infections and the gut microbiota of the colonized human hosts has been established, but few studies explored the gut microbiota of the parasites. This preliminary study aimed to characterize the microbiota of the STH parasite for further understanding the STH parasite-host relationship. The gut microbial genomic DNA from four adult A. lumbricoides worms recovered from a six-year-old indigenous Negrito boy living in an STH-endemic village in Perak, Peninsular Malaysia was extracted and sequenced for the V3-V4 region of the 16S rRNA. The microbiota profiles of these worms were characterized and compared with the gut microbiota of their human host, including the profiles from four STH-positive and three STH-negative individuals from the same tribe and village. The gut microbial structure of A. lumbricoides was found to be differed significantly from their human host. The worms contained lower gut bacterial abundance and diversity than human. This difference was evident in the beta diversity analysis which showed a clear separation between the two sample types. While both Firmicutes (52.3%) and Bacteroidetes (36.6%) are the predominant phyla followed by Proteobacteria (7.2%) in the human gut, the microbiota of Ascaris gut is highly dominated by Firmicutes, constituting 84.2% relative abundance (mainly from the genus Clostridium), followed by Proteobacteria (11.1%), Tenericutes (1.8%) and Bacteroidetes (1.5%). The parasites were also found to alter the microbial structure of the human gut following infection based on the relatively higher bacterial abundance in STH-positive versus STH-negative participants. Further studies with a greater number of Ascaris adults and human hosts are needed to confirm the gut microbiota profiles.